Condenser

ABSTRACT

A condenser is provided that makes a liquid droplet of a liquid phase medium drop effectively, the liquid phase medium residing in a lower end opening of a medium passage of the condenser, thereby preventing any degradation in the performance of the condenser. In the condenser, vapor, which is supplied to a cooling pipe ( 14 ) connected to cooling fins ( 16 ), is cooled, condensed into water, and recovered in a water-collecting tray ( 21 ) provided beneath the cooling pipe ( 14 ), and a needle-shaped member ( 24 ) provided so as to face the lower end opening of the cooling pipe ( 14 ) ruptures the droplet that, due to surface tension, resides in the lower end opening of the cooling pipe ( 14 ) and makes it drop into the water-collecting tray ( 21 ). A plate-form filter can be used instead of the needle-shaped member ( 24 ), and in this case not only can the droplet be made to drop from the lower end opening of the cooling pipe ( 14 ) more effectively due to the capillary action of the filter, but also dust contained in the water can be removed.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/JP01/02111 which has an Internationalfiling date of Mar. 16, 2001, which designated the United States ofAmerica.

FIELD OF THE INVENTION

The present invention relates to a condenser that cools a gas phasemedium, which is supplied to a medium passage connected toheat-releasing means, by heat exchange with the heat-releasing means,and recovers the gas phase medium as a liquid phase medium bycondensation into liquid phase medium recovery means provided beneaththe medium passage.

BACKGROUND ART

Japanese Patent Application Laid-open No. 58-48076 discloses a Rankinecycle system comprising a vane-type expander. This converts the pressureenergy of high temperature high pressure vapor generated in a vaporizeremploying a gas burner as a heat source into mechanical energy via avane-type expander, and the vapor thereby generated, whose temperatureand pressure have decreased, is condensed in a condenser and thenreturned to the vaporizer via a water supply pump.

As shown in FIGS. 9A to 9C, a condenser that condenses and coverts a gasphase medium into a liquid phase medium generally comprises a largenumber of cooling fins 01 that are stacked with gaps through which acooling medium can pass, and a large number of cooling pipes 02 that runvertically through these cooling fins 01, the gas phase medium suppliedfrom the upper end of the cooling pipe 02 being drained of heat by thecooling fins 01, so as to condense into the liquid phase medium whilepassing through the interior of the cooling pipe 02, and dripping fromthe lower end of the cooling pipe 02.

In order to reduce the dimensions of the condenser for condensing andconverting a gas phase medium into a liquid phase medium and maintain ahigh level of heat exchange per unit volume with the gas phase medium,it is necessary to reduce the diameter of the cooling pipe 02, but whenthe cooling pipe 02 is narrow, it is easy for a droplet D that has beenformed into a sphere from the liquid phase medium due to surface tensionto reside in the lower end of the cooling pipe 02 under the influence ofthe surface tension and it becomes difficult for it to drop. When thelower end of the cooling pipe 02 is blocked in this way by the dropletD, it becomes difficult for the gas phase medium to flow through theinterior of the cooling pipe 02, thus greatly degrading the performanceof the condenser, and it is therefore necessary to remove by some meansthe droplet D residing in the lower end of the cooling pipe 02.

DISCLOSURE OF THE INVENTION

The present invention has been carried out in view of theabove-mentioned circumstances, and the object thereof is to promote theeffective dropping of a liquid phase medium that resides in a lower endopening of a medium passage of a condenser, thereby preventing anydegradation in the performance of the condenser.

In order to accomplish the above-mentioned object, in accordance withthe present invention, there is proposed a condenser that cools a gasphase medium, which is supplied to a medium passage connected toheat-releasing means, by heat exchange with the heat-releasing means,and recovers the gas phase medium as a liquid phase medium bycondensation into liquid phase medium recovery means provided beneaththe medium passage, characterized in that the condenser comprisesdroplet rupturing means that makes contact with a droplet of a liquidphase medium that resides in a lower end opening of the medium passage,ruptures the droplet, and recovers the liquid phase medium into theliquid phase medium recovery means.

In accordance with this arrangement, by making the droplet rupturingmeans come into contact with the droplet of the liquid phase medium thatresides in the lower end opening of the medium passage of the condenser,the droplet rupturing means ruptures the droplet, thereby making it dropquickly into the liquid phase medium recovery means via the lower endopening of the medium passage. In this way, it is possible to reduce theperiod of time during which the lower end opening of the medium passageis blocked with the droplet and ensure smooth flow of the gas phasemedium through the medium passage, thereby preventing any degradation inthe performance of the condenser.

Furthermore, in addition to the above-mentioned arrangement, there isproposed a condenser wherein the distance between the lower end openingof the medium passage and the upper end of the droplet rupturing meansis set smaller than the maximum vertical dimension of the droplet.

In accordance with this arrangement, since the upper end of the dropletrupturing means is positioned in the proximity of the lower end openingof the medium passage, the liquid phase medium droplet that resides inthe lower end opening of the medium passage can make contact with thedroplet rupturing means so that it drops before growing large, therebyminimizing the period of time during which the lower end opening of themedium passage is blocked with the droplet.

Moreover, in addition to the above-mentioned arrangement, there isproposed a condenser wherein the droplet rupturing means resonates withexternally input vibration and moves relative to the droplet.

In accordance with this arrangement, since the droplet rupturing meansresonates with the externally input vibration and moves relative to thedroplet, thus increasing the opportunity for the droplet rupturing meansto come into contact with the droplet, the droplet rupturing means canrupture the droplet effectively so as to make it drop via the lower endopening of the medium passage.

Furthermore, in addition to the above-mentioned arrangement, there isproposed a condenser wherein the droplet rupturing means includes afilter for filtering the liquid phase medium.

In accordance with this arrangement, since the droplet rupturing meansincludes the filter, not only can the ruptured droplet be drawn inquickly from the lower end opening of the medium passage by capillaryaction of the filter, but also the droplet thus drawn in can be filteredby the filter so as to remove dust.

A cooling pipe 14 of embodiments corresponds to the medium passage ofthe present invention, a cooling fin 16 of the embodiments correspondsto the heat-releasing means of the present invention, a water-collectingtray 21 of the embodiments corresponds to the liquid phase mediumcollecting means of the present invention, and a needle-shaped member 24and a filter 31 of the embodiments correspond to the droplet rupturingmeans of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 to FIG. 4C show a first embodiment of the present invention.

FIG. 1 is a diagram showing the overall arrangement of a Rankine cyclesystem of an internal combustion engine.

FIG. 2 is a longitudinal cross section of a condenser.

FIG. 3 is a magnified view of an essential part in FIG. 2.

FIG. 4A to FIG. 4C are diagrams for explaining a process in which thedroplet is ruptured.

FIG. 5 to FIG. 6C show a second embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 3 above.

FIG. 6A to FIG. 6C are explanatory diagrams.

FIG. 7 is a view, corresponding to FIG. 3 above, of a third embodimentof the present invention.

FIG. 8 is a view, corresponding to FIG. 3 above, of a fourth embodimentof the present invention.

FIG. 9A to FIG. 9C are diagrams showing the growth of a droplet in acooling pipe of a conventional condenser.

BEST MODE FOR CARRYING OUT THE INVENTION

The first embodiment of the present invention is explained below byreference to FIG. 1 to FIG. 4C.

FIG. 1 shows the overall arrangement of a Rankine cycle system 2 of aninternal combustion engine 1 in which a condenser of the presentinvention is employed, the system including a vaporizer 3 for heatingwater, which is a working medium, using exhaust gas from the internalcombustion engine 1 as a heat source so as to generate high temperaturehigh pressure vapor, an expander 4 for converting the pressure energy ofthe high temperature high pressure vapor into mechanical energy, acondenser 5 for liquefying and condensing the reduced temperaturereduced pressure vapor discharged from the expander 4, and a watersupply pump 6 for pressurizing and supplying water from the condenser 5to the vaporizer 3.

The structure of the condenser 5 is now explained by reference to FIG. 2and FIG. 3.

An upper housing 11 provided in an upper part of the condenser 5 is acontainer-shaped member which has a cylindrical joint 11 a formedintegrally on one end in the longitudinal direction and whose lower faceopening is blocked by welding an upper base plate 12, the joint 11 abeing connected to the expander 4 (see FIG. 1) via a vapor supply pipe13. Fixed to the upper base plate 12 of the upper housing 11 are theupper ends of a large number of vertically extending cooling pipes 14,the vicinities of the lower ends of cooling pipes 14 being fixed to alower base plate 15.

Reducing the diameter of the cooling pipes 14 makes it difficult fordroplets of a liquid phase medium to be removed because of the stronginfluence of capillary action caused by the surface tension of theliquid phase medium, and the droplets that are finally formed willeasily block the interiors of the cooling pipes 14. The droplets willnot drop until the self weight, which depends on the diameter of thedroplets, is in balance with the surface tension and the diameter of thedroplets will grow larger than that of the cooling pipes 14. It has beenfound that by setting the clearance between the ends of the coolingpipes 14 and droplet rupturing means, which will be described later, thesame as or less than the droplet diameter, which is substantiallydetermined by the surface tension of the liquid phase medium, thedroplets generated from the liquid phase medium can be rupturedefficiently. The cooling pipes 14 have upper end openings, which are cutoff at right angles, running through the upper base plate 12 andcommunicating with the inner space of the upper housing 11 anddiagonally cut lower end openings running through the lower base plate15 and extending downward. Stacked via a fixed space between the upperbase plate 12 and the lower base plate 15 are a large number of coolingfins 16, which are thin metal sheets, the cooling pipes 14 runningvertically through these cooling fins 16. The cooling fins 16 and thecooling pipes 14 are in intimate contact with each other at arunning-through portion without any gaps so that heat transfer iscarried out efficiently.

A lower housing 17 whose upper end is welded to an outer peripheral partof the lower base plate 15 has a flange 17 a formed by bending outwardan outer peripheral part of a lower end of the lower housing 17.Superimposed on the lower face of the flange 17 a are a first seal 18,an outer peripheral part of a partition 19, a second seal 20, and aflange 21 a of a water collecting tray 21, the flange 21 a being formedby bending outward an outer peripheral part of the upper end of thewater-collecting tray 21, which has an open upper face, and all thereofbeing fastened together by a plurality of bolts 22 and nuts 23. Formedin the partition 19 are a large number of openings 19 a facing the lowerend openings of the cooling pipes 14, and formed on the upper face ofthe partition 19 are a large number of needle-shaped members 24 bent ina crank shape. The extremity of each of the needle-shaped members 24extends upward and faces the lower end opening of the correspondingcooling pipe 14.

The lower face of the water-collecting tray 21 is inclined so that oneend thereof in the longitudinal direction is low, and a nut 25 is weldedto the lower face of the lowest section of the water-collecting tray 21.A bottomed cylindrical ceramic strainer 28 is fixed to a joint 27screwed into the nut 25 via a seal 26, and an upper part of the ceramicstrainer 28 passes through an opening 21 b of the water-collecting tray21 and extends into the inner space of the water-collecting tray 21. Thejoint 27 is connected to the water supply pump 6 (see FIG. 1) via awater drain pipe 29.

The action of the condenser 5 having the above-mentioned arrangement isnow explained.

The vapor, as the gas phase medium, supplied from the expander 4 to theinterior of the upper housing 11 of the condenser 5 via the vapor supplypipe 13 is cooled by contact with the inner walls of the cooling pipes14 while entering them from the inner space of the upper housing 11 andflowing downward in the cooling pipes 14. The cooling pipes 14 whosetemperature has increased by heat exchange with the vapor are cooled byheat exchange with the cooling fins 16 exposed to cooling air. The gasphase vapor cooled within the cooling pipes 14 condenses into liquidphase water, flows down along the surface of the walls of the coolingpipes 14, reaches the lower end openings, and forms the sphericaldroplets D by the action of surface tension (see FIG. 4A).

In order for the droplet to drop spontaneously from the lower endopening of the cooling pipes 14, as shown in FIG. 9C, it is necessaryfor the droplet D to grow so that the vertical dimension of the dropletD (the distance between the lower end of the droplet D and the centerposition of the diagonally cut lower end opening of the cooling pipe 14)becomes at least a length a, but since the length b (see FIG. 3) fromthe opening of the cooling pipe 14 to the upper end of the needle-shapedmember 24 is set shorter than a in this embodiment, the droplet D comesinto contact with the upper end of the needle-shaped member 24 before itgrows to a size at which it will drop spontaneously. As a result, thedroplet D is ruptured, flows along the needle-shaped member 24 (see FIG.4B), and drops onto the water-collecting tray 21 via the opening 19 a ofthe partition 19 beneath the needle-shaped member 24 (see FIG. 4C).

Water that has thus dropped onto the water-collecting tray 21 via theopenings 19 a of the partition 19 from the large number of cooling pipes14 is filtered through the ceramic strainer 28 provided at the lowestpoint of the water-collecting tray 21, and then supplied to the watersupply pump 6 via the water drain pipe 29.

As hereinbefore described, since the droplets D that reside in the lowerend openings of the cooling pipes 14 are forcibly ruptured with theneedle-shaped members 24 so that they drop, the lower end openings ofthe cooling pipes 14 can be opened before the droplets D grow large,thus ensuring smooth flow of the vapor within the cooling pipes 14 andthereby enhancing the condensation effect. In this case, if theneedle-shaped members 24 are water-repellent, the droplets D cannot beruptured effectively, and it is therefore preferable to form theneedle-shaped members 24 using a hydrophilic member or coat them with ahydrophilic member. Furthermore, it is preferable for the surfacetension of the needle-shaped members 24, which are droplet rupturingmeans, to be greater than that of the cooling pipes 14 and that of thedroplets.

When the vibration accompanying operation of the internal combustionengine 1 or the expander 4 is transmitted to the condenser 5, since thepartition 19 of the condenser 5 and the needle-shaped members 24provided thereon resonate, the opportunity for the needle-shaped members24 to make contact with the droplets D increases, and the needle-shapedmembers 24 break up the surface of the droplets D, thereby furtherpromoting rupture of the droplets D. Resonance of the cooling pipes 14themselves can also promote the dropping of the droplets D.

It is also possible to attach a mass to a part of the partition 19 forthe purpose of promoting the resonance of the partition 19. The lowerend openings of the cooling pipes 14 are diagonally cut so as to makeseparation of the droplets D easy.

Next, the second embodiment of the present invention is explained byreference to FIG. 5 to FIG. 6C.

A condenser 5 of the second embodiment comprises, instead of theneedle-shaped members 24 of the condenser 5 of the first embodiment, asheet-form filter 31, which is superimposed on the upper face of apartition 19. A first seal 18 and a flange 17 a of a lower housing 17are superimposed on the upper face of a metal gasket 32 supporting anouter peripheral part of the filter 31; a partition 19, a second seal20, and a flange 21 a of a water-collecting tray 21 are superimposed onthe lower face of the metal gasket 32; and all thereof are fastenedtogether by bolts 22 and nuts 23.

Provision of the gasket 32 can not only prevent the filter 31 fromdeforming due to the tightening force of the bolts 22 and prevent waterfrom leaking through the outer periphery of the filter 31, but can alsomake the filter 31 resonate effectively, thereby enhancing the effect ofrupturing the droplets D. In the present embodiment, the length b (seeFIG. 5) from openings of cooling pipes 14 to the upper end of the filter31 is set shorter than the maximum vertical dimension a of the dropletsD. Although a metal or a polymer can be employed as a material for thefilter 31, it is desirable for the material to be hydrophilic.

As shown in FIG. 6A, when the droplet D grows in the lower end openingof the cooling pipe 14 and the lower end of the droplet D comes intocontact with the upper face of the filter 31, as shown in FIG. 6B, thedroplet D is ruptured and is quickly drawn in from the lower end openingof the cooling pipe 14 by the capillary action of the filter 31. Asshown in FIG. 6C, the water is filtered of dust by the filter 31, dropsdown onto the water-collecting tray 21, and is collected.

In addition to the function and effect of the first embodiment, thesecond embodiment can further attain the effects of quickly drawing inthe droplets D by the capillary action of the filter 31 and removingdust by the filtration effect of the filter 31. Moreover, provision ofthe filter 31 can reduce the size of a ceramic strainer 28 or eliminatethe ceramic strainer 28 because of the filtration effect of the filter31. That is, the provision of the filter 31 can minimize the amount ofdust that reaches the ceramic strainer 28, particularly if the diameterof dust that can filter through the filter 31 is set larger than thediameter of dust that can filter through the ceramic strainer 28; sincelarge dust is filtered out by the filter 31, the ceramic strainer 28only needs to filter out dust having a small diameter, and as a resultits filtration effect can be maintained over a long period of time,thereby increasing the lifespan thereof.

Next, the third embodiment of the present invention is explained byreference to FIG. 7.

The third embodiment is an improvement of the second embodiment; itemploys a filter 31 made of a fluffy material, and needle-shaped fibers31 a project out of the upper face thereof toward lower end openings ofcooling pipes 14.

In accordance with the third embodiment, since the needle-shaped fibers31 a projecting from the filter 31 stick into droplets D growing in thelower end openings of the cooling pipes 14, the droplets D can beruptured more effectively and absorbed by the filter 31.

Next, the fourth embodiment of the present invention is explained byreference to FIG. 8.

The third embodiment is an improvement of the first embodiment; itemploys a filter 31 stacked on the lower face of a partition 19, thefilter 31 being the same as that in the second embodiment.

In accordance with the fourth embodiment, droplets D that have beenruptured by contact with needle-shaped members 24 can be quickly drawnin by the capillary action of the filter 31. Furthermore, since thefilter 31 can remove dust contained in the water, it is possible toreduce the size of a ceramic strainer 28 or eliminate the ceramicstrainer 28 because of the filtration effect of the filter 31. That is,the provision of the filter 31 can minimize the amount of dust thatreaches the ceramic strainer 28, particularly if the diameter of dustthat can filter through the filter 31 is set larger than the diameter ofdust that can filter through the ceramic strainer 28; since large dustis filtered out by the filter 31, the ceramic strainer 28 only needs tofilter out dust having a small diameter, and as a result its filtrationeffect can be maintained over a long period of time, thereby increasingthe lifespan thereof.

Although embodiments of the present invention are explained in detailabove, the present invention can be modified in a variety of wayswithout departing from the spirit and scope of the present invention.

For example, the droplet rupturing means is not limited to theneedle-shaped members 24 and the filter 31 illustrated in theembodiments.

Furthermore, the cooling pipes 14 having a circular cross section areillustrated as the medium passage in the embodiments, but a pipe havinga cross section other than a circle or a passage formed between twoplates may be employed.

Moreover, the air-cooled cooling fins 16 are illustrated as theheat-releasing means in the embodiments, but a water-cooled water jacketmay be used. Furthermore, the cooling medium is not limited to air orwater, and any type of cooling medium having different coolingperformance characteristics can be employed.

Moreover, the condenser 5 of the Rankine cycle system 2 is illustratedin the embodiments; the present invention can be applied to a condenser5 for any purpose, and its medium is not limited to water either.

Furthermore, the partition 19 and the water-collecting tray 21 aredetachably fixed by the bolt 22 and the nut 23 in the embodiments, butthey may be fixed using a clip, etc. so as to be detached easily,thereby enhancing the convenience of maintenance.

INDUSTRIAL APPLICABILITY

As hereinbefore described, the condenser related to the presentinvention can be desirably applied to the liquefaction of vapor that haspassed through an expander of a Rankine cycle system, but it is notlimited to the Rankine cycle system and can also be used for any otherpurpose; in this case it is not limited to water and can be applied toany other medium.

1. A condenser, comprising: a medium passage to which is supplied a gasphase medium that is to be cooled; heat-releasing means connected to themedium passage, the gas phase medium being cooled by heat exchange withthe heat-releasing means; liquid phase medium recovery means providedbeneath the medium passage, the gas phase medium being recovered as aliquid phase medium by condensation into the liquid phase mediumrecovery means; and droplet rupturing means that makes contact with adroplet of the liquid phase medium that resides in a lower end openingof the medium passage, ruptures the droplet, and recovers the liquidphase medium into the liquid phase medium recovery means, wherein thedroplet rupturing means is a needle-shaped member bent in a crank shape,an extremity of the needle-shaped member extending upward and facing alower end opening of the medium passage.
 2. The condenser according toclaim 1, wherein the liquid phase medium is recovered into the liquidphase medium recovery means via an opening of a partition beneath thedroplet rupturing means.
 3. The condenser according to claim 1, whereina lower face of the liquid phase recovery means is inclined so that oneend of the liquid phase recovery means in the longitudinal direction islower than the opposite end.
 4. The condenser according to claim 1,wherein the droplet rupturing means is a sheet-form filter which quicklydraws the droplet by a capillary action and removes dust from thedroplet.
 5. The condenser according to claim 1, wherein the dropletrupturing means is at least one of the needle-shaped member and asheet-form filter.
 6. A condenser, comprising: a medium passage to whichis supplied a gas phase medium that is to be cooled; heat-releasingmeans connected to the medium passage, the gas phase medium being cooledby heat exchange with the heat-releasing means; liquid phase mediumrecovery means provided beneath the medium passage, the gas phase mediumbeing recovered as a liquid phase medium by condensation into the liquidphase medium recovery means; and droplet rupturing means that makescontact with a droplet of the liquid phase medium that resides in alower end opening of the medium passage, ruptures the droplet, andrecovers the liquid phase medium into the liquid phase medium recoverymeans, wherein the distance between the lower end opening of the mediumpassage and the upper end of the droplet rupturing means is set smallerthat the maximum vertical dimension of the droplet.
 7. A condenser,comprising: a medium passage to which is supplied a gas phase mediumthat is to be cooled; heat-releasing means connected to the mediumpassage, the gas phase medium being cooled by heat exchange with theheat-releasing means; liquid phase medium recovery means providedbeneath the medium passage, the gas phase medium being recovered as aliquid phase medium by condensation into the liquid phase mediumrecovery means; and droplet rupturing means that makes contact with adroplet of the liquid phase medium that resides in a lower end openingof the medium passage, ruptures the droplet, and recovers the liquidphase medium into the liquid phase medium recovery means, wherein thedroplet rupturing means resonates with externally input vibration andmoves relative to the droplet.
 8. A condenser, comprising: a mediumpassage to which is supplied a gas phase medium that is to be cooled;heat-releasing means connected to the medium passage, the gas phasemedium being cooled by heat exchange with the heat-releasing means;liquid phase medium recovery means provided beneath the medium passage,the gas phase medium being recovered as a liquid phase medium bycondensation into the liquid phase medium recovery means; and dropletrupturing means that makes contact with a droplet of the liquid phasemedium that resides in a lower end opening of the medium passage,ruptures the droplet, and recovers the liquid phase medium into theliquid phase medium recovery means, wherein the droplet rupturing meansincludes a filter for filtering the liquid phase medium.